EditText的文本不可见

Question

这是我的布局代码

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:map="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">


    <include
        android:id="@+id/include"
        layout="@layout/app_bar"
        android:layout_width="0dp"
        android:layout_height="90dp"
        map:layout_constraintEnd_toEndOf="parent"
        map:layout_constraintStart_toStartOf="parent"
        map:layout_constraintTop_toTopOf="parent" />

    <fragment
        android:id="@+id/activity_home_map"
        android:name="com.google.android.gms.maps.SupportMapFragment"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        map:layout_constraintBottom_toBottomOf="parent"
        map:layout_constraintEnd_toEndOf="parent"
        map:layout_constraintStart_toStartOf="parent"
        map:layout_constraintTop_toBottomOf="@id/include" />


    <android.support.v7.widget.CardView
        cardElevation="3dp"
        cardUseCompatPadding="true"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="20dp"
        android:layout_marginStart="20dp"
        android:layout_marginTop="75dp"
        android:backgroundTint="@android:color/holo_blue_bright"
        map:layout_constraintEnd_toEndOf="parent"
        map:layout_constraintStart_toStartOf="parent"
        map:layout_constraintTop_toTopOf="@+id/include">


        <android.support.constraint.ConstraintLayout
            android:id="@+id/constraintLayout"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <View
                android:id="@+id/activity_home_view_green"
                android:layout_width="10dp"
                android:layout_height="10dp"
                android:layout_marginStart="20dp"
                android:background="@drawable/circle"
                map:layout_constraintBottom_toBottomOf="@+id/textView3"
                map:layout_constraintStart_toStartOf="parent"
                map:layout_constraintTop_toTopOf="@+id/textView3" />


            <TextView
                android:id="@+id/textView3"
                android:layout_width="wrap_content"
                android:layout_height="20dp"
                android:layout_marginBottom="8dp"
                android:layout_marginStart="20dp"
                android:layout_marginTop="8dp"
                android:text="My Location"
                map:layout_constraintBottom_toTopOf="@+id/guideline3"
                map:layout_constraintStart_toEndOf="@+id/activity_home_view_green"
                map:layout_constraintTop_toTopOf="parent" />

            <View

                android:id="@+id/view3"
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:layout_marginEnd="20dp"
                android:layout_marginStart="20dp"
                android:layout_marginTop="8dp"
                android:background="@android:color/darker_gray"
                map:layout_constraintEnd_toEndOf="parent"
                map:layout_constraintHorizontal_bias="0.0"
                map:layout_constraintStart_toStartOf="parent"
                map:layout_constraintTop_toTopOf="@id/guideline3" />


            <View
                android:id="@+id/activity_home_view_gray"
                android:layout_width="10dp"
                android:layout_height="10dp"
                android:layout_marginStart="20dp"
                android:layout_marginTop="8dp"
                android:background="@drawable/circle1"
                map:layout_constraintBottom_toBottomOf="@+id/activity_home_et"
                map:layout_constraintStart_toStartOf="parent"
                map:layout_constraintTop_toBottomOf="@+id/view3" />

            <EditText
                android:id="@+id/activity_home_et"
                android:layout_width="0dp"
                android:layout_height="20dp"
                android:layout_marginBottom="8dp"
                android:layout_marginEnd="20dp"
                android:layout_marginStart="20dp"
                android:layout_marginTop="40dp"
                android:hint="Where are you going?"
                android:textColor="@android:color/black"
                map:layout_constraintBottom_toBottomOf="parent"
                map:layout_constraintEnd_toEndOf="parent"
                map:layout_constraintStart_toEndOf="@+id/activity_home_view_gray"
                map:layout_constraintTop_toTopOf="@+id/guideline3" />

            <android.support.constraint.Guideline
                android:id="@+id/guideline3"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                map:layout_constraintGuide_begin="50dp" />


        </android.support.constraint.ConstraintLayout>

    </android.support.v7.widget.CardView>

    <pritish.sawant.com.androiddevslopesuberclone.CustomProgressBarInButton.CircularProgressButton
        android:id="@+id/activity_home_request_ride_btn"
        android:layout_width="0dp"
        android:layout_height="50dp"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="30dp"
        android:layout_marginStart="30dp"
        android:background="@drawable/button_background"
        android:gravity="center"
        android:text="REQUEST RIDE"
        android:textSize="20sp"
        map:layout_constraintBottom_toBottomOf="parent"
        map:layout_constraintEnd_toEndOf="parent"
        map:layout_constraintStart_toStartOf="parent"
        tools:fontFamily="@font/changa_one" />

    <ImageView
        android:id="@+id/activity_home_iv_centerme"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:scaleType="centerInside"
        map:layout_constraintBottom_toTopOf="@+id/activity_home_request_ride_btn"
        map:layout_constraintEnd_toEndOf="parent"
        map:srcCompat="@mipmap/centermapbtn" />


</android.support.constraint.ConstraintLayout>

我从卡片视图中删除了一些与问题无关的不需要的视图。我尝试为卡片视图的背景设置不同的颜色，以避免edittext和cardview之间的颜色冲突，但仍然不可见。我甚至尝试删除卡片视图，但我的编辑文本中的文字仍然不可见。